Preparation of alkylated aromatic hydrocarbons and sulfonation thereof



Patented Nov. 21, 1950 sci-Manda c nemat c: V @Nq' Application October 1a, 1941,

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SerialNo. muss 6 Claims. (01. 260-450) This invention relates to a method of producing alkyl aryl sulfonates, primarily useful as detergents, but also useful as surface active agents, wetting agents, and emulsifying agents. More particularly, this invention is concerned with the production of such compounds from-the olefinic materials present in hydrocarbon fractions derived from a Fischer-Tropsch process.

The production of phenyl alkane sulfonate detergents usually involves an allgvlation or condensation reaction between olefins and an arcmatic hydrocarbon, usually benzene, to produce a phenyl alkane compound, followed by a sulfonation of the phenyl alkane compound. A paramount problem in the production of a suitable sulfonate detergent has been the rovision of a supply of suitable olefins for the alkylation or condensation reaction. Branched chain aliphatic olefins, such as butene polymers, introduce outstanding difllculties because of the instability of these olefins during the alkylation or condensation reactions. In alkylation and condensation reactions with benzene or toluene, there results a degradation of the olefins when excessively branched chain aliphatic olefins are employed. This degradation leads to the production of a mixture of phenyl alkanes containing compounds both lower and higher in allphatic molecular weight than the olefin originally selected and desired. The instability and degradation of such olefin polymers in the presence of condensation catalysts during alkylating conditions also leads to thqproduction of substantially inseparable poly-alkylated aromatics of the same molecular weight and boiling range as the desired phenyl alkane. This is a decided disadvantage since, upon conversion to the sulfonated phenyl derivatives, relatively low yields have resulted. The sulfonated derivatives tend to be relatively poor in detergent quality and require costly purification treatment to eliminate or reduce odor, unsulfonatable residue, color bodies, and other impurities introduced by degradation caused by the original instability of the olefin polymer. a

n the other hand, straight chain olefins, particularly l-oleflns, do not have these disadvantages, but heretofore straight chain olefins have been of limited availability and prohibitive in 'cost. Thus, olefinic hydrocarbons of suitable molecular weight for the production of sulfonated phenyl alkane detergents have been available from the cracking by thermal or catalytic processes of petroleum hydrocarbons. While the exact chemical nature of these oleflnic materials is not known, they contain naphthenic and aromatic hydrocarbons in addition to olefinic hydrocarbons and exhibit instability and degradation when utilized as a source of olefins in the desired alkylation or condensation reactions. It has now been found that the hydrocarbons obtained from a Fischer-Tropsch hydrocarbon synthesis contain oleflns within the molecular weight and boiling point range required for the production of detergents, which olefins are substantially only l-olefins with little branched chains, so that the olefins derived from this source are highly suitable for the production of desirable phenyl alkane compounds by alkylation or condensation reactions. The olefins .derived from Fischer- Tropsch hydrocarbons exhibit little degradation or fragmentation and therefore allow the production of desired phenyl alkane materials with a low consumption of the aromatic hydrocarbons. On sulfonation of the phenyl alkanes produced using olefins derived from Fischer-Tropsch hydrocarbons there, however, normally is derived a detergent material of inferior quality. The detergent so produced is particularly characterized by inferior wetting powers and odor.

It has been found that the low quality of the alkyl benzene sulfonate detergents produced from the use of Fischer-Tropsch olefins is not due to the character of the olefin hydrocarbons themselves from such a source, but rather to the impurities other than olefins normally accompanying such Fischer-Tropsch olefins. The impurities which degrade the quality of the phenyl alkane sulfonate detergents appear to be principally oxygen compounds, particularly aldehydes and ketones. By the use of a separation procedure these oxygen compounds may be readily separated from the Fischer-Tropsch hydrocarbons, and as a result, there is produced a form of olefin-containing stock which is highly desirable for the production of sulfonated phenyl alkane detergents. By the use of such a stock it is possible to produce detergents light in color, free of odor and of high quality in respect to foaming properties, detergency properties and wetting properties.

The purification of Fischer-Tropsch olefin stocks from the oxygen compounds detrimental to the production of desirable detergents may be carried out in various manners, but it has been found that the production of high quality detergents has not so-inuch depended upon the manner of removal of the oxygen compounds as it has upon the completeness of the removal of such compounds however effected. Moreover, it

3 is not believed necessary that all of the oxygen compounds be separated from the olefin stock employed; the principal impurities giving rise to detergents of objectionable odor and color are found to be carbonyls, aldehydes or ketones, and possibly certain organic acids. These carbonyl and acid compounds may be removed from the Fischer-Tropsch olefin stock in a number of ways, such, for example, as treating the stocks with hot caustic solutions or with sodium bisulfite. By such treatments it is possible to remove from the olefin stock substantially all the oxygen compounds except hydroxy or alcohol compounds. The olefin stocks thus produced may then be utilized for the production of sulfonated phenyl alkane detergents of good quality. Complete removal of oxygen compounds from the olefin stocks. remaining after the caustic or sodium sulfite treatment may be effected in a variety of ways, such, for example, as extraction with solvents. The remaining oxygen compounds are principally higher boiling point alcohols which may be extracted by solvents, such, for example, as methanol. These higher boiling point alcohols might also be removed by azeotropic distillation, such materials as butylene glycol being used for the third phase. A particularly satisfactory method is the use of boric acid solutions. By the use of boric acid solutions to promote esterification of the higher alcohols, esters are forms which may be readily separated by distillation in accordance with the well-known I. G. Farben process.

While the foregoing methods of removing oxygen compounds may be employed, it has been found that the purification of the olefins by adsorbents such as activated carbon and silica gel is to be preferred. By the use of a silica gel adsorption, not only is it possible to obtain a separation of olefins and paraflins from Fischer- Tropsch hydrocarbons with complete removal of oxygenated compounds, but it is also possible to separate the olefins from aromatic hydrocarbons. As a result, an olefin-containing hydrocarbon stock is readily derived in one operation which is a superior stock in all respects for the production of sulfonated phenyl alkane detergents. By the use of such a stock, not only are detergents of highest quality produced, but they are produced in a most economical manner with a minimum number of reactions of constituents, such, for example, as benzene.

While in the foregoing description we have referred to the use of benzene for the production of phenyl alkanes and sulfonated phenyl alkane detergents, the reaction of olefinic stocks with toluene to form tolyl alkanes and the sulfonation of such tolyl alkanes to form sulfonated tolyl alkane detergents follow the same rules, so that detergents of highest quality may be produced by first removing from the olefins the carbonyl compounds, and using the purified olefinic stocks thus derived for the production of such sulfonated tolyl alkane detergents.

It is an object of this invention, therefore, to provide a process of producing phenyl and tolyl alkanes and sulfonated phenyl and tolyl alkane detergents from Fischer-Tropsch hydrocarbons, which products are free of odoriferous constituents, such as aldehydes and ketones.

It is another object of the present invention to provide a process of producing phenyl and tolyl alkanes and sulfonated phenyl and tolyl alkane detergents in which degradation of olefin stock and fragmentation are substantially eliminated and by which detergents may be economically and efficiently produced, which detergents are of high quality.

Other objects and advantages of the process of the present invention will become apparent 5 from the following description of a preferred example of the invention.

Fischer-Tropsch hydrocarbons are derived by hydrocarbon synthesis of hydrogen and carbon monoxide. Such syntheses are performed by passing the hydrogen and carbon monoxide at high temperatures over a catalyst. The particular type of catalytic reaction utilized does not substantially alter the character of the products produced,,although it may alter considerably the proportion of the different products, such as oxygenated compounds, olefins and parafllns produced. In the particular example of the process herein described ,the Fischer-Tropsch hydrocarbons were obtained bypassing mainly hydrogen and carbon monoxide over an iron al.- kali catalyst at a temperature of about 600 F. and 300 pounds pressure. By cooling the gases emitting from the reaction first to a temperature of about 350 F. to remove waxes followed by cooling to about 100 F. to separate an oil fraction from the water produced in the process, the hydrocarbons utilized were obtained. The hydrocarbons were then subjected to fractional distillation to separate out an olefin stock having the particular molecular weight or boiling points suitable for the manufacture of detergents.

In order to produce efficient sulfonated phenyl and tolyl alkane surface active agents useful as detergents and wetting agents, it is necessary to select the alkane portion in such manner that its hydrophobic character will be sufliciently counterbalanced by the hydrophilic character of the sulfonate grouping to the proper degree. In order to obtain in the product the desired properties, the alkane portion of the molecule should not contain too few or too many carbon atoms. In general, the alkane portion of the molecule should contain not less than 8 carbon atoms nor more than carbon atoms, and it is preferable to restrict this variation to a narrower range,

such as between 12 and 15 carbon atoms in order to produce materials of the greatest efficiency.

This balance between the hydrophobic and hydrophilic character is conventiently determined in the case of the sulfonated alkanes derived from oleflnic materials by the boiling point range of the oleflnic material. A hydrocarbon fraction boiling between 300 F. and 600 F. at atmospheric pressure is utilized where it is desired to produce products the alkane portion of which contains between 8 and 20 carbon atoms. It is desirable to use a hydrocarbon fraction boiling between 350 F. and 500 F. at atmospheric pressure. About 95% of the olefinic constituents in such a hydrocarbon fraction will contain between 12 and 15 carbon atoms.

In the particular example given, there was employed a Fischer-Tropsch fraction having an A. S. T. M. distillation of start 360,- 5%--371;

10%-374; 50%400; 90%-443; 95%465; and end point 571. The bromine number of this stock was 63.5, the carbonyl number 28.9, hydroxy number 27.8, and neutralization number 12.4, the carbonyl number and hydroxy number being determined, respectively, by the methods described in J. A. C. S. 57, 57, 1935, and J. A. C. S.

57, 61, 1935, from which analysis it was estimated that the stock contained 63.5% olefins; 12.6%

carbonyl compounds; 12.7% hydroxy compounds, and 4.2% acids. There was, therefore, at least assmai 7% of knownfnon-oleflnic hydrocarbons orparamns present.

terials through a column containing '28 to- 200 mesh silica gel. Silica gel is active adsorbent possessing the properties of adsorbing many types ofcheriiical compounds. Compounds will be adsorbed to. diiferent degrees, depending upon I Q 15% removed and their chemical structure and polarity. It is,

therefore, possible even with'compounds with relatively small diiferences in polarity to effect separations of mixtures into their constituents or into groups of constituents having similar polarities and having similar chemical structures. In such an adsorption treatment as applied to Fischer-Tropsch hydrocarbons, the paraflln constituents tend to come through the column first, followed thereafter by the olefinic materials, the aromatic compounds, if any present, following the olefinic material, the oxygen compounds being most strongly retained by silica gel.

In passing this fraction of Fischer-Tropsch hydrocarbons through the silica gel column, it was found that the bromine number of the fractions emerging from the column steadily increased until about 60% of the material has passed through a the column, after which the bromine number of the material coming through the column diminished. The first 60% of the material passing through the column was therefore separated stock for further treatment. This stock exhibited a bromine number of 68, while the carbonyl number, hydroxy number and neutralization number of the stock are zero, from which it was calculated that the stock now consisted solely of olefins and parafiins in proportions of approximately 69% olefins and 31% parailins. By the process, therefore, substantially complete removal of carbonyl compounds, hydroxy compounds and acidic compounds from the olefinic material was attained in one operation. Examination of the olefin material retained indicated that it was substantially exclusively l-olefins having little branched chain structure.

This olefin stock was then utilized for the preparation of mono-phenyl alkanes. For this purpose, any well-known method of alkylating aromatics might be employed. Alkylation is carried out, for example, by use of the Friedel- Crafts type condensation catalyst, such, for example, as A1Cl3, H2804, HF, BF'3, or mixture of BF: and HF, a particularly effective catalyst being hydrogen fluoride. In this case hydrogen fluoride was employed as the catalyst and the alkylation was carried out by the process more fully described in the Tinker and Weinmayr U. S. Patent No. 2,275,312. About four parts of benzene were mixed with 1 part of the silica gel treated olefinic material to be processed. The ratio, however, of benzene to olefinic material is not critical and may vary over considerable limits. A temperature of 100 F. was selected as a suitable temperature of treatment. Treated product was then separated and washed and the unreacted benzene distilled off. In the d stillation, approximately the middle 70% of the prodnot was separated from the remainder by distillation, yielding a product having a boiling point range at atmospheric pressure of 525 F. to 650 F. In distilling the product, about the first tained was found to contain pr'ix'icipally paraf fins.'whlle about thegbottom 15%1discarded from.

= .,-.:the. product;-retained appeared tofibe' only higher i 1 molecular wcightjalkyl aromatics. .Theporti'on .oiithe product retained consisted mainlyof alkyl I benzenes within theboiling'point and molecular? I range suitable for; the production of sulfonated phenyl alkane detergents. i

' fraction was subjected to carried out by any 'usualprocessof sulfonating alkyl aromatics, using sulfuric acid of strength such as from 98% 'to 20%'fumlng-or higherf sulfonation was carriedout by the use of 20% fuming acid using about 3 moles of sulfuric acid per mole of hydrocarbon material. Temperatures of about 110 F. to 140 F. may be employed, but the temperature range of 130 F. to 140 F. was utilized. The unsulfonated oil was then separated from the sulfonated oil, the unsulfonated residue being about 3.3%. The product was then neutralized with sodium hydroxide to produce a mixture of sodium sulfonate and sodium sulfate. The ratio of sodium sulfonates to sodium sulfates was then adjusted to 40:60. The product produced was odorless, a 1% aqueous solution thereof giving a 20 color by the Saybolt the sulfonated phenyl alkanes thus produced from using Fischer-Tropsch olefins were fully equal, if not superior, to previously known defrom the remainder of the material as the olefin tergents of this class in Such Properties While in the example just described the benzene was reacted with the purified olefins to produce first a phenyl alkane which was thereafter sulfonated to produce the desired detergent, either benzene or toluene may be utilized to orm such a, desired alkyl aryl sulfonate detergent. By the substitution in the example given of toluene for benzene in a substantially similar manner, a tolyl alkane is first produced which is then sulfonated in a substantially similar manner to produce the sulfonated tolyl alkane detergent.

While the particular example of the invention herein described is well adapted to carry out the objects of the present invention, it is obvious that various modifications and changes may be made, and this invention includes such modifications and changes as come within the scope of the appended claims.

We claim:

1. A process which comprises passing a fraction of the reaction product of a Fischer-Trospch synthesis boiling in the range about 300 F. to 600 F. through a mass of solid adsorbent conforming substantially to silica gel in its adsorptive properties at a temperature substantially below that at which cracking occurs to separate an adsorbate and a percolate, segregating a fraction of the percolate which has flowed from the adsorbent mass when the bromine number of the eflluent percolate is at approximately its maximum valueand alkylating a mononuclear aromatic hydrocarbon with at least a portion of the segregated fraction.

2. A process which comprises treating a Fischer-Tropsch olefinic hydrocarbon fraction boiling within the range of from 300 F. to 600 F, at a temperature substantially below that at which cracking occurs with a solid absorbent conforming substantially to silica gel in its adsorptlvo lated from the product re- A uHonafion 7i the usual1'manner. While s'ulfon'ation may be properties, capable of removing carbonyl compounds therefrom, and selectively adsorbing said carbonyl compounds on said solid adsorbent, recovering said Fischer-Tropsch olefinic hydrocarbon fraction with carbonyl compounds thereby removed, alkylating a mononuclear aromatic hydrocarbon therewith, and separating from the resulting alkylate an alkyl aromatic fraction having an alkyl group containing from 8 to 20 carbon atoms.

3. A process of preparing a sull'onated aryl alkane detergent, which comprises subjecting a hydrocarbon fraction boiling under normal pressures between 300 F. and 600 F.-to a silica gel adsorption treatment at a temperature substantially below that at which cracking occurs, said hydrocarbon fraction before treatment containing olefins and carbonyl compounds and consisting essentially'of reaction products of the synthesis of hydrocarbons by reaction of hydrogen and carbon monoxide, separating by said silica gel adsorption treatment a fraction containing olefin constituents free of carbonyl compounds, alkylating an aromatic hydrocarbon of the group consisting of benzene and toluene with said latter fraction to form aryl alkanes, and sulfonating said aryl alkanes.

4. A process of preparing a sulfonated aryl alkane detergent, which comprises subjecting a hydrocarbon fraction boiling under normal pressures between 350 F. and 500 F. to a Silica gel adsorption treatment at a temperature substantially below that at which cracking occurs, said hydrocarbon fraction before treatment containing olefins and carbonyl compounds and consisting essentially of reaction products of the synthesis of hydrocarbons by reactionof hydrogen and carbon monoxide, separating by said silica gel adsorption treatment a fraction containing olefin constituents free of carbonyl compounds, alkylating an aromatic hydrocarbon of the group consisting of benzene and toluene with said latter fraction to form aryl alkanes, and sulfonating said aryl alkanes.

5. A process of preparing sulfonated aryl a1- kane detergents, which comprises subjecting a hydrocarbon fraction consisting essentially of reaction products of the synthesis of hydrocarbons by reaction of hydrogen and carbon monoxide boiling under normal pressures between 300 F. and 600 F. and containing oleflns and carbonyl compounds to silica gel adsorption treatment at a temperature substantially below that at which cracking occurs, separating a fraction of the hydrocarbo'ns containing olefin constituents and substantially free of carbonyl constituents, said fraction being a high bromine number first portion of hydrocarbons passing through a silica gel adsorbent, alkylating an aromatic hydrocarbon of the group consisting of benzene and toluene with said fraction to form aryl alkanes, and sulfonating the aryl alkanes so produced,

6. A process of preparing sulfonated aryl al kane detergents, which comprises subjecting to a silica gel adsorption treatment a hydrocarbon fraction consisting essentially of reaction products of the synthesis of hydrocarbons by reaction of hydrogen and carbon monoxide, said hydrocarbon fraction boiling under normal pressures between 300" F. and 600 F., the silica gel treatment being carried out by passing the fraction through a column of silica gel adsorbent at a temperature substantially below that at which cracking occurs, separating a portion of the fraction passing from the silica gel adsorption column prior to decrease in the bromine number of the material passing from the adsorbent, alkylating benzene with the fraction so separated to form aryl alkanes, and sulfonating said aryl alkanes.

JOHN Q. COPE. JOHN W. SCO'I'I, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,106,071 Stanton Jan. 18, 1938 2,161,173 Kyrides June 6, 1939 2,232,117 Kyrides Feb. 18, 1941 2,260,617 Hancock Oct. 28, 1941 2,264,427 Asbury Dec. 2, 1941 2,398,101 Lipkin Apr. 9, 1946 2,422,627 Martin et a1 June 17, 1947 OTHER REFERENCES Mair et al., J. Res. Nat. Bureau of Standards, vol. 15, pages 51-62 (1935).

Mair et al., J. Res. Nat. Bureau of Standards, v01. 32, pages -183 (1943).

Mair et al., J Res. Nat. Bureau of Standards, vol. 32, pages 151-164 (1943).

Suter Organic Chemistry of Sulfur, Wiley 8: Sons, Inc., New York, 1944, p. 206.

Mair, J. Res. Nat. Bureau of Standards, vol. 34, pages 435-451 (1945).

Hirschler et al., Ind. Eng. Chem., vol. 39, December 1947, pages 1585-1596 (presented before Div. of Petroleum Chem. at 111th Meeting of ACS, Atlantic City, April 14 to 18, 1947, abstract p 3-0). 

1. A PROCESS WHICH COMPRISES PASSING A FRACTION OF THE REACTION PRODUCT OF A FISCHER-TROSPCH SYNTHESIS BOILING IN THE RANGE ABOUT 300*F. TO 600*F. THROUGH A MASS OF SOLID ADSORBENT CONFORMING SUBSTANTIALLY TO SILICA GEL IN ITS ADSORPTIVE PROPERTIES AT A TEMPERATURE SUBSTANTIALLY BELOW THAT AT WHICH CRACKING OCCURS TO SEPARATE AN ADSORBATE AND AND PERCOLATE, SEGREGATING A FRACTION OF THE PERCOLKATE WHICH HAS FLOWED FROM THE ADSORBENT MASS WHEN THE BROMINE NUMBER OF THE EFFUENT PERCOLATE IS AT APPROXIMATELY ITS MAXIMUM VALUE AND ALKYLATING A MONONUCLEAR AROMATIC HYDROCARBON WITH AT LEAST A PORTION OF THE SEGREGATED FRACTION. 